Solenoid



Dec. 8, 1942. A. DIEBOLD SOLENOID Fi led June 6, 1941 INVENTOR /v .0/59040 uuv mwwifl 6065063 36 3 0 0 010 0 0 0 0 0 06 0 0 0 000 000 000000 0 .Q. ...A,...0 O 0 0 0 0 0 0 0 0 0 0 0 0v 0 \0 V .0 0 0 0 0 0 0. 0 0 0 0 0 0 0 0. 0 0 05 0 0 0 0 0 0 0 0 A a i l 3 mi Q Patented Dec. 8, 1942 SOLENGID Anton Diebold, New York. N. Y., assignor to Signal Service Corporation, a corporation of Delaware Application June 6, 1941, Serial No. 396,820

This invention relates to solenoids of the plunger type, an object being to provide a construction which, upon energization, will bring the armature surely and accurately to a deadstop in the zero position, that is, the position of minimum reluctance, without overshooting and without oscillation.

A more specific object is to effect the deadstop action of the armature without the noise and momentary oscillation incident to mechanical stops, or the sluggishness and uncertainty characteristic of devices designed to absorb the momentum of the armature, either by use of a dash-pot or by producing mechanical friction to brake the movement.

In accordance with this invention I produce the desired dead-stop effect by magnetic braking which is the consequence of the design of the armature. The armature itself is provided with pole faces of substantially the same area as that of the pole faces of the core ofthe solenoid and spaced so as to oppose coincidentally the respective poles of the core. The reluctance is minimum when the movable pole faces directly oppose the stationary pole faces, and since the magnetic pull increases rapidly with the displacement of the pole faces and counter to the direction of displacement, the armature is drawn positively and directly to its zero position and any substantial overshooting is prevented.

More specifically the armature plunger is of the axial length of the core sections which are U-shape with the ends of their legs opposing each other to constitut the poles. v The solenoid is lined with a rectangular tube of non-magnetic material, such as brass, to guide the plunger in its axial movements, the tube stopping short of the solenoid pole faces which are opposed by the armature pole faces. The ends of the armature therefore fit within and are guided by the tube, the intermediate portion of the armature being of reduced cross-section. Alternatively the polar ends of the armature may be single or double faced; in other words, the armature may be U- shape or I-shape. The armature is flanked on either side by non-magnetic guide strips which are of a uniform width to fit within the guide tube and have extensions for operative attachment to the part to be actuated by thesolenoid. I shall now describe the specific embodiment of the invention illustrated in the drawing, and shall thereafter point out my invention in claims.

In the drawing: Fig. 1 is a perspective view of the solenoid; Fig. 2 is a longitudinal section;

Fig. 3 is a transverse section on line 3-3 of r Fig. 2;

Fig. 4 is a perspective view of an armature such as shown in Fig. 2;

Fig. 5 is a section similar to Fig. 2 but showing a slight modification in the form of the armature; and

Fig. 6 is a perspective view of the armature shown in Fig. 5.

Referring to the drawing, the solenoid includes a coil 2 and a core consisting of legs 3, arranged parallel to each other, and legs 4 extending at right angles to the legs 3, said legs 4 forming pole pieces which face each other. An armature 5 is freely movable within the coil 2 and between the pole pieces 4. r

In the construction shown in Figs. 2 and 3, the armature is substantially rectangular in crosssection and is provided with a recess 6 extending longitudinally of the armature for a distance substantially equal to that between the inner margins l of the pole pieces 4. Thus are formed projecting portions 8 on each end of the armature and with the armature in its zero position, as shown in Fig. 2, the projecting portions 8 are positioned opposite the pole pieces I and coincide therewith.

The core is made up of laminations 9 secured together by rivets l0. Suitable angle brackets ll, Figs. 1 and 3, may be provided whereby the solenoid may conveniently be mounted.

The armature may also consist of laminations secured together by rivets l2.

The armature is guided by means of a sleeve ll, Fig. 3, of non-magnetic material, as for instance, brass.

The angle brackets I may have extensions spanning the coil 2 and extending across the respective ends of the pole pieces I, and secured by rivets to the pole pieces and to the sleeve H as shown, thereby fastening the cores and sleeve together and securing the parts into a unitary structure.

In the construction shown in Fig. 2 the sleeve H on that side of the armature provided with the recess 6, is cut away at either end so that it does not cover the poles of the core. Its inner edge, however, is in the same plane as the faces of the poles between which that portion of the sleeve extends, as clearly shown in Fig. 2. The other three faces of the armature may be surrounded by this sleeve which may extend to the outer margins It -I6 of the core.

The armature laminations extend only between the outer margins l6-l6 when the armature is in its zero position shown in Figs. 1, 2 and 5. In other words, the portion of the armature containing magnetically permeable material extends only between these outer margins lS-li. Under these conditions, therefore, the armature is subjected to the maximum magnetic forces holding it in its zero position and any movement beyond such position, either way, is strongly resisted. The amount of resistance is a factor of the depth of the recess 6.

In order that the armature may conveniently be used to cause some mechanical movement it is provided with legs i! which legs preferably extend the full length of the armature on two sides thereof as shown in Figs. 3, 4 and 6 and are formed of non-magnetic material.

In Figs. 5 and 6 a slightly different form of armature is shown. This form differs from Fig. 2, only in that the recess 8 is provided on two opposite sides of the armature and the sleeve H is cut away on both sides instead of on only one side as in Fig. 2.

What I claim is:

l. A solenoid comprising a hollow cylindrical coil, a non-magnetic sleeve substantially rectangular in cross section fitting axially within the coil and extending beyond the ends thereof, a magnetic core having two U-shape elements disposed upon the coil in an axial plane with their ends alined and constituting at each end a pair of pole pieces facing each other and embracing the extending end of the sleeve, the extending sleeve ends having their side toward one of the elements removed and the pole faces of that element being flush with the inner face of the sleeve, and a rectangular plunger armature freely slidable and fitting within the sleeve and having its side toward the exposed pole faces recessed for a distance substantially equal to that between the inner margins of the pole faces, whereby the armature is substantially U-shape and the reluctance of the flux path is least when the recess is central of the pole faces.

2. A solenoid comprising a hollow cylindrical coil, a non-magnetic sleeve substantially rectangular in cross section fitting axially within the coil and extending beyond the ends thereof, a magnetic core having two U-shape elements disposed upon the coil in an axial plane with their ends alined and constituting at each end a pair of pole pieces facing each other and embracing the extending end of the sleeve, the extending sleeve ends having their sides toward the two pole faces removed and the pole faces being flush with the inner face of the sleeve, and a rectangular plunger armature freely slidable and fitting within the sleeve and having its opposite sides toward the exposed pole faces recessed for a distance substantially equal to that between the inner margins of the pole faces, whereby the armature is substantially I-shape and the reluctance of the flux path is least when the recessed portion of the plunger is central of the pole faces.

ANTON DIEBOLD. 

